This is an intriguing take on the theme with really interesting puzzle opportunities! I love the mechanic of moving the light source to raise/lower the character/shadow. However, at times it could hard to tell which was actually standing on the ground. Maybe an indicator or highlight could be added to whichever character is actually in control of the jumping? And as others have said, it would be helpful if there was some indication of the light source.
There are also some small glitches, but they didn't detract too much from the experience, and I was able to mostly avoid them once I knew about them.
This game kind of reminds me of old Indonesian shadow puppet theater called Wayang. Thematically, I think it would also be cool if the main character was like a shadow puppet of some kind.
Overall, this is a really cool concept, even if it is a bit rough around the edges!